Process of reducing metallic oxides to the metallic state



(No Model.)

L. G. LAUREAU.

PROCESS OF REDUCING METALLIC OXIDES TO THE, METALLIOSTATE.

N0. 420,945. I r Patented Feb. 11 1890.

.J' f' '1 Y E3 g, mw am W: k W S UNITED STATES PATENT OFFICE;

LOUIS G. LAUREAU, OF PHILADELPHIA, PENNSYLVANIA.

PROCESS OF REDUCING METALLIC OXIDEQ TO THE METALLIC STATE.

SPECIFICATION forming part of Letters Patent No. 420,945, dated February11, 1890- Application filed March 8, 1889. $erial No. 302,442, (Nomodel.

To all whom it may concern.-

Be it known that I, LOUIS G. LAUREAU, of Philadelphia, and State ofPennsylvania, have invented certain new and useful Improvements inProcesses of Reducing Metallic Oxides to the Metallic State, of whichthe following is a specification.

In the execution of my improved process I employ natural gas orequivalent hyd rocarbons.

Heretofore, so far as I know, in attempts at reduction of ores by meansof natural gas the result has been defeated by the deposits of solidcarbon from the gas.-

TVhile the employment of natural gas is my main contemplation, it isalso in contemplation to employ the waste hydrocarbons resulting fromthe distillation of petroleum.

In the execution of my process I combine with the hydrocarbon an amountof oxygen suflicient to transform the carbon of the gas into carbonicoxide. ,1 heat the hydrocarbon to the temperature of dissociation ofcarbon, the carbon then uniting with the oxygen, the result beingcarbonic oxide and hydrogen, both reducing agents. I heat theseresulting gases to the proper temperature for reduction and inject themthus heated to the metallic oxides to be treated. I thereby reduce theoxides to the state of metallic sponge, which may be bloomed or meltedand run into ingots.

In the accompanying drawings I show an apparatus merely exemplifying inits character adapted for the execution of my improved process.

In the drawings, Figure 1 is a central vertical section 5 Fig. 2,avertical section on line X X, and Fig. 3 a horizontal section on lineIn the drawings, A represents the main reductionstack; B, ducts leadingthereinto; C,

enlarged intermediate portions of these ducts,

Q drocarbon under pressure and leading to the I tuyeres; J, aregulating-cock in the hydrocarbon-pipe; K, a pipe to be connected witha source of air-supply under pressure, and, connecting, in common withthe hydrocarbonpipe, with the tuyeres; L, a regulating-cock in theair-supply pipe; M, the base of the reduction-stack arranged in'a'common manner for the withdrawal of the reduced ore.

Having determined from the composition of the hydrocarbon the amount ofoxygen required to transform its carbon to carbonic oxide, I adjust thesupply of air and hydrocarbon to the tuyeres accordingly. I then fillthe stack with ore broken into small pieces and close the top gas-tight.I then build fires in the hearths and get the coils of pipe in thechambers to'a cherry-red heat. I-then admit the mixed gas and airthrough the tuyeres. The mixture passes over the heating-coils and theoxygen of the air acts at once, combining with the carbon of thehydrocarbon, forming carbonic oxide, the hydrogen remaining free. As thedecomposition of the hydrocarbon does not absorb so much heat as thecombination of carbon and oxygen into carbonic oxide generates, there isa necessary surplus of heat, which is communicated to the heating-coils.Therefore, after the operation is once started, but little heat need becommunicated by means of the hearths. The hearths may be fired, or theymay be fed with the resulting gases of reduction, and any system forsupplying heat to the mixed gases may be substituted for the one shownin the exemplification. The carbonic oxide having been formed and havingattained the temperature at which reduction is active, it, together withthe hydrogen, passes to the 'stack and communicates its sensible heat tothe ore. The body of ore does not at once reach the temperature ofreduction, which is between 550 and 1,000 centigrade; but an equilibriumis gradually reached, after which the operation goes on uninterruptedly.The extraction of the reduced ore takes place at regular intervals atthe base of the stack.

The nitrogen of the air, injected with the IOO perature within bounds,thus preventing the fusing of the ores and consequent stoppage ofreduction.

The ores of most metals found in nature as oxides-such as copper, iron,manganese, &c.can be reduced by my process by varying the temperature ofthe gases between 550 and 1,000 Centigrade, according to the differentmetals and physical structures of the ores. Iron ore, for instance, ifin the shape of a light hematite, is well reduced at a temperature of000 centigrade, while the hard magnetites require up to 7 50 centigrade.Manganese ores require up to 900 cen tigrade.

I claim asmy invention The improvement in processes for reducingmetallic oxides to the metallic state, which consists in mixinghydrocarbon gas with atmospheric air in such proportion that the oxygenof the air will transform the carbon of the hydrocarbon into carbonicoxide, subjecting the mixture to the temperature of combination ofoxygen and carbon and such higher temperature as the ore reduction callsfor, and injecting the carbonic oxide, hydrogen, and nitrogen thusformed into the mass of ore to be treated.

LOUIS G. LAUREAU. \Vitnesscs:

J. W. SEE, CHARLES F. ZIEGLER.

